How many bones are there in a baby's body? How many bones are there in a baby's body? Two hundred and six Three hundred and six Six hundred and three How many centimeters are there in a kilometer? How many centimeters are there in a kilometer? a hundred ten thousand a hundred thousand What's the population of the USA? What's the population of the USA? about two hundred million about four hundred million about three hundred million How many countries are there in the world? How many countries are there in the world? about a hundred and twenty about a hundred and ninety about ninety How many seconds are there in an hour? How many seconds are there in an hour? sixty three thousand six hundred thirty-six thousand How many kilometers is the Moon from the Earth? How many kilometers is the Moon from the Earth? about forty thousand about four hundred thousand about four million